It is well known that the preparation of aluminoxanes by reaction of a trialkylaluminum and water is very exothermic and requires great care in achieving the careful, controlled and incomplete hydrolysis of the trialkylaluminum to yield the desired product. Various method have been proposed to achieve this result including the general approach of contacting the water reagent in a controlled manner with the trialkylaluminum in a suitable organic solvent.
Use of hydrated salts, such as CuSO.sub.4 .multidot.5H.sub.2 O, Fe(SO.sub.4).multidot.5H.sub.2 O, or Al.sub.2 (SO.sub.4).sub.3 .multidot.16H.sub.2 O has been employed as a means of controlling the reactivity of water with a trialkylaluminum (see, for example, U.S. Pat. Nos. 4,544,762 and 4,665,208).
U.S. Pat. No. 3,300,458 to R. M. Manyik et al. taught that a water-wetted solvent stream could be contacted with a calculated amount of an anhydrous solution of the trialkylaluminum reagent to bring about the reaction to produce the desired aluminoxane. Such an approach uses relatively large amount of solvent since two solvent streams, each combining one of the reactants, are used.
H. Sinn et al. in "Some New Results on MethylAluminoxane", "Transition Metals and Organometallics as Catalysts for Olefin Polymerization", W. Kaminsky et al. eds., Springer-Verlag, Berlin, Heidleberg, 1988, 257-268 indicates (on page 257) that Sakharovskaya et al. used "a nitrogen stream" as a carrier for the water vapor used in the reaction forming aluminoxanes. A careful analysis of the footnoted British Patent No. 1,319,746, however, fails to reveal such a teaching. The process suggested by this British citation involves the hydrolysis of trialkylaluminum with water in a tertiary alkyl amine medium. However, an earlier publication in 62 Chem. Abstr. 2787d (1965) speaks of the use of nitrogen containing moisture and oxygen in the reaction with a trialkylaluminum reagent.
S. Amdurski et al. in J. Inorg. Nucl. Chem., 1961, Vol. 23, pp. 133-134 indicates that the reaction between triethylaluminum and water can be suitably moderated by adding water "vapour" to the triethyl aluminum. A similar disclosure exists in J. Am. Chem. Soc. 90:12, June 1968, pp. 3173-3177 by A. Storr et al., in which a hydrolytic method is described (on pp. 3173-3174) in which water was provided to a limb of the apparatus apart from the section of the apparatus holding the solvent containing the alkylaluminum reagent. Warming of the limb holding the water turns it into a vapor which can diffuse into the solvent/aluminum alkyl solution.
More recently, U.S. Pat. Nos. 4,730,072 to G. W. Schoenthal et al. and 4,772,736 to D. N. Edwards et al. propose the use of a high degree of agitation within the solution to disperse a water stream when it comes into contact with the solution containing the trialkylaluminum reagent to thereby insure the desired controlled hydrolysis of the trialkylaluminum reagent. Analogously, U.S. Pat. No. 4,730,071 to G. W. Schoenthal et al. uses ultrasonic vibrational treatment of the organic solution containing the water to achieve dispersion of the water in the solvent medium.
Most recently, U.S. Pat. No. 4,908,463 to S. A. Bottelkerghe has suggested impinging a solution of a hydrocarbylaluminum in an inert solvent carrier with a water dispersion in an inert solvent in a T-shaped reactor. The highly turbulent water dispersion is formed by passing a solvent/water mixture through a static mixer.